Chikara Tashiro

Low dose intrathecal morphine and pain relief following caesarean section.

Healthy women who underwent caesarean section under spinal anaesthesia were studied to determine the extent of postoperative analgesia and side-effects produced by low doses of intrathecal morphine. Patients were randomly allocated to receive, in double-blind fashion, 0 mg (group 1: control group), 0.05 mg (group 2), 0.1 mg (group 3), or 0.2 mg (group 4) of morphine, with 10 mg tetracaine in 10% dextrose 2.5 ml. (n = 20 x 4 groups). The effect of intrathecal morphine was examined in terms of the duration until the first supplemental analgesic was needed and the numbers of the doses within the first postoperative 48 h. Pain relief was significantly greater in groups 3 and 4 than in group 1. The incidence of nausea, vomiting and pruritus increased in a dose-dependent manner. No patient developed respiratory depression. Our results suggest that postoperative analgesia lasts more than 24 h with 0.1 mg or 0.2 mg of intrathecal morphine. Since the incidence of side-effects was higher at 0.2 mg, 0.1 mg may be the optimum dose for caesarean section.

The NMDA receptor NR2A subunit regulates proliferation of MKN45 human gastric cancer cells

The present study investigated proliferation of MKN28 and MKN45 human gastric cancer cells regulated by the N-methyl-d-aspartate (NMDA) receptor subunit. The NMDA receptor antagonist dl-2-amino-5-phosphonovaleric acid (AP5) inhibited proliferation of MKN45 cells, but not MKN28 cells. Of the NMDA subunits such as NR1, NR2 (2A, 2B, 2C, and 2D), and NR3 (3A and 3B), all the NMDA subunit mRNAs except for the NR2B subunit mRNA were expressed in both MKN28 and MKN45 cells. MKN45 cells were characterized by higher expression of the NR2A subunit mRNA and lower expression of the NR1 subunit mRNA, but MKN28 otherwise by higher expression of the NR1 subunit mRNA and lower expression of the NR2A subunit mRNA. MKN45 cell proliferation was also inhibited by silencing the NR2A subunit-targeted gene. For MKN45 cells, AP5 or knocking-down the NR2A subunit increased the proportion of cells in the G(1) phase of cell cycling and decreased the proportion in the S/G(2) phase. The results of the present study, thus, suggest that blockage of NMDA receptors including the NR2A subunit suppresses MKN45 cell proliferation due to cell cycle arrest at the G(1) phase; in other words, the NR2A subunit promotes MKN45 cell proliferation by accelerating cell cycling.

Comparison of optic laryngoscope Airtraq ® and Miller laryngoscope for tracheal intubation during infant cardiopulmonary resuscitation

BACKGROUND Recent resuscitation guidelines for infant cardiopulmonary resuscitation (CPR) emphasize that all rescuers should minimize interruption of chest compressions, even for endotracheal intubation. We compared the utility of the Miller laryngoscope (Mil) with Airtraq (ATQ) during chest compression in an infant manikin. METHODS Twenty staff doctors in intensive care and emergency medicine performed tracheal intubation on an infant manikin with Mil and ATQ with or without chest compression. RESULTS In Mil trials, no participants failed without chest compression, but 6 of them failed during chest compression (P < 0.05). In ATQ trials, all participants successfully secured the airway regardless of chest compression. Intubation time was significantly lengthened due to chest compression in Mil trials, but not in ATQ trials. The visual analog scale (VAS) for laryngoscope image did not significantly change due to chest compression for ATQ or Mil trials. In contrast, chest compression worsened VAS scores for tube passage through the glottis in Mil trials, but not in ATQ trials. CONCLUSION We conclude that ATQ performed better than Mil for endotracheal intubation during chest compression in infant simulations managed by expert doctors.

Comparison of air-Q® and Soft Seal® laryngeal mask for airway management by novice doctors during infant chest compression: A manikin study

BACKGROUND Recent resuscitation guidelines for infant cardiopulmonary resuscitation (CPR) emphasise that rescuers should minimise the interruption of chest compressions. To that end, supraglottic devices such as laryngeal mask airways (LMAs) are suggested as a backup for airway management during infant CPR. We therefore compared the utility of the air-Q(®) LMA (air-Q) with that of the Soft Seal(®) LMA (Soft Seal) for infant CPR in an infant manikin. METHODS Twenty-four novice doctors in the anaesthesia department performed insertion and ventilation with air-Q and Soft Seal on an infant manikin with or without chest compression. RESULTS Two doctors failed to insert the Soft Seal without chest compression, while nine failed during chest compression (P<0.05). However, only one doctor failed to insert the air-Q without chest compression, and two doctors failed during chest compression. Insertion time was not significantly increased with chest compression using either device. Insertion time during chest compression was significantly shorter for the air-Q than for the Soft Seal (P<0.05). The visual analogue scale (VAS) was used to evaluate difficulty of use (0mm (extremely easy) to 100mm (extremely difficult)). VAS scores did not change significantly by the addition of chest compression with either device; however, VAS scores during chest compression were significantly higher with Soft Seal than with the air-Q device. CONCLUSION We conclude that novice doctors find the air-Q easier to use than Soft Seal for emergency airway management during chest compression in infants, in an infant manikin.

The effects of dexmedetomidine and halothane on Fos expression in the spinal dorsal horn using a rat postoperative pain model.

We investigated the effect of an intrathecal injection of a selective alpha2 adrenergic receptor agonist, dexmedetomidine (Dex), and halothane anesthesia on Fos expression in the lumbar spinal dorsal horn after skin incision of the plantar surface of the hind paw, a postoperative pain model using rats. Fos immunoreactivity was induced particularly in the superficial layers of the spinal cord 2 h after surgery. Halothane anesthesia (0.5-1.5%) partially reversed Fos induction, but not in a dose-dependent manner. Preoperative spinal Dex (0.1-10 microg) dose-dependently reduced Fos immunoreactivity, while a relatively high dose of Dex (10 microg) was necessary to produce a profound effect. When used with halothane anesthesia, relatively low doses of Dex (1-3 microg) completely suppressed Fos induction in the superficial spinal layers. These findings indicate that preoperative Dex treatment may provide anesthesia that does not induce stress on spinal neurons.

Simple high-performance liquid chromatographic assay of propofol in human and rat plasma and various rat tissues.

jector (SIL-10AD; Shimadzu), and column oven (CTO10AS; Shimadzu). A Symmetry C18 column (3.5-μm, 4.6 100mm; Waters, Tokyo, Japan) was selected for the separation of propofol. The temperature of the column oven was set at 40°C. The mobile phase consisted of acetonitrile and water (60 :40, vol/vol), which was equilibrated at 1.5ml ·min 1. The fluorimetric detector was used for quantifying propofol, and the concentration of propofol was estimated based on the integrated peak area. The excitation and emission wavelengths for the fluorescence detection of propofol were set at 276 and 310nm, respectively [3]. Various rat tissues (brain, liver, kidney, and adipose and muscle tissues) harvested from rats anesthetized with pentobarbital (40mg·kg 1 i.p.) were rinsed with chilled saline to remove contamination with blood. The tissues were subdivided into small pieces with a scalpel and placed in homogenization vessels to prepare homogenates. The mobile phase, equal to nine times the tissue weight, was then added, and the tissue was homogenized at 2000rpm to a uniform slurry (Digital Homogenizer; Iuchi, Osaka, Japan). To 100μl of plasma or 10% tissue homogenate, 1000μl of acetonitrile was added and mixed thoroughly in a vortex mixer. The mixture was centrifuged at 15000g for 10min at 4°C. Then, 10μl of the clear supernatant was directly injected onto the HPLC column. The samples for the calibration curves were prepared from an acetonitrile solution containing propofol at various concentrations. The acetonitrile solutions of propofol were diluted 50 times with plasma or 10% tissue homogenate to obtain the final concentrations of 0, 0.05, 0.2, 1.0, 2.0, 5.0, and 10μg·ml 1 or per gram of wet tissue. The integrated peak area was plotted against the known concentrations of propofol, and calibration curves were constructed by linear regression (Microsoft Office 97 Excel; Tokyo, Japan). The slopes of calibration curves constructed with human plasma and various rat tissues were compared with oneway analysis of variance. If the analysis of variance Address correspondence to: Y.-L. He Received: February 8, 2001 / Accepted: August 28, 2001

The influences of maternal albumin concentrations on the placental transfer of propofol in human dually perfused cotyledon in vitro

IMPLICATIONS These results indicate that fetal exposure to propofol can vary considerably depending on maternal plasma albumin concentration. A fractional change in the maternal protein binding of propofol can result in a relatively large difference in fetal exposure.

Emulsion of flurbiprofen axetil reduces propofol injection pain due to a decrease in free propofol concentration

PurposeFlurbiprofen axetil emulsion (FA), a prodrug of nonsteroidal anti-inflammatory drugs (NSAIDs) that is widely used for perioperative pain relief in Japan, has been effective for reducing propofol injection pain, but the mechanism is unclear. The purpose of this study was to test the hypothesis that the reduction of propofol injection pain by FA may be attributed to a decrease in free propofol concentration.MethodsDiprivan (propofol emulsion; Dipri; AstraZeneca, Cheshire, UK) and Propofol-Lipuro (Lipuro; B. Braun, Melsungen, Germany) were used. A randomized double-blind study was performed to compare pain on injection with six kinds of propofol solution: plain Dipri, a 3 : 1 (v/v) mixture of Dipri and saline (Dipri-S), a 3 : 1 mixture of Dipri and FA (Dipri-FA), plain Lipuro, a 3 : 1 mixture of Lipuro and saline (Lipuro-S), and a 3 : 1 mixture of Lipuro and FA (Lipuro-FA). Three hundred patients (American Society of Anesthesiologists [ASA] physical status [PS] I–II) scheduled for elective surgery received one of these six propofol emulsions (n = 50, each group). Injection pain was evaluated every 10 s after the start of a 1-min infusion of up to 2 mg·kg−1 propofol. We also measured the in vitro free propofol concentrations of the propofol preparations that we tested (n = 5, each).ResultsThe mixture of FA with propofol decreased the incidence of injection pain, compared with plain propofol, for Lipuro (P < 0.01) but not for Dipri. The free propofol concentration in each emulsion in vitro was also decreased by mixing the propofol with saline or FA. The incidence of pain was reduced in a free-propofol concentration-dependent manner (R2 = 0.926).ConclusionThe findings suggest that the reduction of propofol injection pain by FA may be explained, at least in part, by a reduction in the free propofol concentration.

Nitric oxide (NO) measurement accuracy.

Background. Evaluation of the clinical utility of NO requires accurateassessment of inspired [NO]. Currently, chemiluminescence analyzersare the clinical standard for analysis; however, their performance in theclinical setting has not been systemically evaluated. Methods. We evaluatedthe performance of four chemiluminescence analyzers (270B NOA, SieversInstruments, Inc.; CLA 510S, Horiba Co., Ltd.; CLD 700 AL, Eco Physics Corp.;Model 42, Thermo Environmental Instruments Inc.) in simulated clinicalsettings. Transport delay and dynamic 95% response time were measured by theballoon in a glass chamber puncture technique. Fluctuating [NO] ina continuous flow of gas and [NO] during mechanical ventilation,where NO was premixed prior to entering the ventilator, were evaluated.Results. Transport delay ranged from 1.02 ± 0.02 to 24.36 ± 2.47s (p < 0.05) and the 95% response time ranged from 0.22 ± 0.04 to70.03 ± 0.03 s (p < 0.05). Accurate analysis of [NO] ina continuous flow system was only possible with the most rapid responseanalyzer (270B NOA). All other analyzers under reported the maximum[NO] (p < 0.05) and over reported the minimum [NO] (p< 0.05). All analyzers accurately determined [NO] in theinspiratory limb of the ventilator circuit, but none accurately determined[NO] at the airway opening. Conclusions. Measurements of inhaled[NO] can vary greatly, dependent upon the performancecharacteristics of the analyzer and the location of NO analysis. All studiesevaluating the clinical use of NO should fully describe the technical gasdelivery methodology and the response time and transport delay of thechemiluminescence analyzer used.

Comparison of placental transfer of local anesthetics in perfusates with different pH values in a human cotyledon model

PurposeWe aimed to investigate the placental transfer of local anesthetics in perfusates with different pH values, using a dual-perfused human cotyledon model.MethodsThe dual-perfused human cotyledon model was prepared from placentas obtained following cesarean delivery (n = 5). Protein-free solution was perfused through both maternal and fetal arteries. Four amide-type local anesthetics (mepivacaine [Mep]; lidocaine [Lid]; bupivacaine [Bup]; and ropivacaine [Rop]) were added to the maternal perfusate at 1 µg·ml−1. Three conditions were tested (stage 1, maternal pH 7.4, fetal pH 7.4; stage 2, maternal pH 7.4, fetal pH 6.9; and stage 3, maternal pH 6.9, fetal pH 6.9). Venous blood samples were collected from the fetal circuit after stabilization. The fetal vein/maternal artery concentration ratio (F/M ratio) of the local anesthetics was used as an index of placental transfer. The concentration of human chorionic gonadotropin (hCG) in the maternal vein was measured at the end of each stage.ResultsThe F/M ratios in all stages were in the order of: Mep > Lid > Bup ≒ Rop. The F/M ratios of Mep were significantly higher than those of the other local anesthetics in all stages. The F/M ratios of Lid were higher than those of Rop in stages 2 and 3. The F/M ratios of Lid and Rop were higher in stage 2 than in stage 3. However, the differences between the F/M ratios in the three stages were not as large as expected from the basic uncharged ([B]) condition and pH gap. The concentration of hCG showed a time-dependent decrease with increasing stage (stage 1, 81.0 ± 58.9 mIU·ml−1; stage 2, 57.4 ± 31.8 mIU·ml−1; stage 3, 32.1 ± 19.7 mIU·ml−1).ConclusionOur data clearly show that it is the basic uncharged concentration that mainly determines the placental transfer of amide-type local anesthetics with protein-free perfusate. This finding suggests that Rop and Bup can be used more safely than Mep in terms of placental transfer.